.dropdown:hover .dropdown-content {
  display: block;
}
ul{
    list-style-type: none;
}
a{
    text-decoration:none;
    color: white;
    font-size: 20px;
}
.daohang{
	width: 100%;
	height: 70px;
	background-color: rgba(0, 0, 0, 0.8);
}
.daohang ul {
	width: 80%;
	height: 100%;
}
.daohang ul li {
	width: 100px;
	height: 100%;
	float: left;
	text-align: center;
	line-height: 70px;
        margin-left: 120px;
}
.dropdown{
    float: left;
    width: 150px;
    height: 250px;
}
video{
    width: 100%;
    height: 50%;
}
.c{
    float: right;
    position: relative;
    line-height: 70px;
    margin-left: 60px;
}
.c a{
    float: right;
    color: whitesmoke;
    font-size: 25px;
}